Abstract—Well logging records can help to answer many questions from a wide range of special interested information and basic petrophysical properties to formation evaluation of oil and gas reservoirs. The accurate calculations of porosity in carbonate reservoirs are the most challenging aspects of the well logging analysis. Many equations have been developed over the years based on known physi...

The Lower Cretaceous Carbonate deposits of the Dariyan Formation of the HighZagros Belt are mainly composed of thick to medium bedded limestone. These depositscontain abundant and diversified benthic foraminifera which have been recovered fromcarbonate rocks. A rich assemblage of microfossils with characteristic: Palorbitolinalenticularis (Blumenbach), Mesorbitolina subconcava (Leymerie), Mesor...

Soil degradation, including rocky desertification, of the karst regions in China is severe. Karst landscapes are especially sensitive to soil degradation as carbonate rocks are nutrient-poor and easily eroded. Understanding the balance between soil formation and soil erosion is critical for long-term soil sustainability, yet little is known about the initial soil forming processes on karst terr...

Contrary to common expectations, the hydroxyl scavengers, carbonate and bicarbonate, are able to enhance the phototransformation by nitrate of a number of substituted phenols. Carbonate and bicarbonate, in addition to modifying the solution pH, are also able to induce a considerable formation of the carbonate radicals upon nitrate photolysis. The higher availability of less-reactive species tha...

Carbonates. The dominant aqueous deposits in ALH 84001 are carbonate minerals, which form ellipsoids, discs, and other space-filling shapes, Figure 1 [1,4,5,6 etc]. These deposits are chemically zoned, nearly continuously from calcitic and ankeritic cores to magnesite-siderite compositions ranging from nearly pure magnesite to ~Mg45Fe45Ca10 (Fig. 2); hydromagnesite is not reported. The carbonat...

Rate coefficients have beenmeasured at 298 K and atmospheric pressure for the reaction of OH radicals and Cl atoms with propylene carbonate. The measurements were performed in a large volume photoreactor using in situ FTIR spectroscopy for the analysis. The following rate coefficients (in units of cm per molecule per s) were obtained: k(OH + PC) 1⁄4 (2.52 0.51) 10 12 and k(Cl + PC) 1⁄4 (1.77 0....

Sea urchin larvae have an endoskeleton consisting of two calcitic spicules. We reconstructed various stages of the formation pathway of calcium carbonate from calcium ions in sea water to mineral deposition and integration into the forming spicules. Monitoring calcium uptake with the fluorescent dye calcein shows that calcium ions first penetrate the embryo and later are deposited intracellular...

Carbonate minerals provide critical information for defining atmosphere-hydrosphere interactions. Carbonate minerals in the Martian meteorite ALH 84001 have been dated to ∼ 3.9 Ga, and both C and O-triple isotopes can be used to decipher the planet's climate history. Here we report Δ(17)O, δ(18)O, and δ(13)C data of ALH 84001 of at least two varieties of carbonates, using a stepped acid dissolu...

The evolutionary success of planktic calcifiers during the Phanerozoic stabilized the climate system by introducing a new mechanism that acts to buffer ocean carbonate-ion concentration: the saturation-dependent preservation of carbonate in sea-floor sediments. Before this, buffering was primarily accomplished by adjustment of shallow-water carbonate deposition to balance oceanic inputs from we...